Thermoelectric intermetallics of yesterday, today... and tomorrow

It will soon be two centuries since Seebeck discovered thermoelectric power, and today only a handful of materials have figures of thermoelectric merit high enough to be reasonably used in converters. What's more, the only thermoelectric modules on the market today, designed for near-ambient temperature applications, are made from a single type of material, bismuth telluride. The search for materials capable of converting thermal energy into electrical energy and vice versa has for many years identified the criteria that such materials should ideally meet. However, due to the interdependence of electrical and thermal transport properties, the number of "good" thermoelectric materials is still very limited. The aim of this seminar is therefore to briefly describe the ideal criteria for thermoelectric materials and to show that, thanks to new synthesis and analysis techniques, new materials are emerging (antimonides, tellurides, selenides and even sulfides), while older materials (Bi2Te3, PbTe, SiGe) are constantly being improved.